Mesoscopic Aggregation of Folded Proteins

折叠蛋白质的介观聚集

• 批准号: 0843726
• 负责人: Vassiliy Lubchenko
• 金额: $ 43.5万
• 依托单位: University of Houston
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-02-01 至 2014-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0843726&HistoricalAwards=false
• 关键词: Mesoscopic; Aggregation; Folded; Proteins

To perform their function, proteins must operate in the crowded environment of a living cell, thus requiring mechanisms that prevent protein aggregation. When these mechanisms fail, pathological conditions, such as sickle cell anemia or plaque formation, take place. In some cases, on the other hand, specific types of aggregation are actually desirable; examples including storage of insulin in the pancreas and protein in grains, in the form of crystals. Making protein crystals remains the single most important tool for protein structure determination, which is crucial for understanding protein function. It comes as a surprise that for those protein aggregates to form, folded protein molecules must first organize into long-lived clusters of a protein-rich liquid that are about a micron in size: According to the existing paradigms of phase equilibrium, such mesoscopic clusters should not exist, nor have they been seen in other similar systems such as colloids. The project aims to elucidate the molecular mechanism and the thermodynamic basis of how the puzzling mesoscopic clusters form. To accomplish this goal, the project will combine the theoretical and experimental efforts of the Lubchenko and Vekilov labs using four proteins as model systems: lysozyme, hemoglobin, insulin, and lumazine synthase. The roles of water structuring at the protein-solvent interface and the formation of transient protein oligomers in the stabilization of the protein-rich phase will be investigated by molecular modeling and tested by means of dynamic/static light scattering and thermodynamic and rheological characterizations. The rich kinetics of the formation/decay of clusters resulting from the interplay between protein transport and oligomer formation will be worked out by solving non-linear kinetic schemes coupled with diffusion/advection and tested against measured life-times and sizes of the clusters. The solution of the important problem of mesoscopic aggregates in concentrated protein solutions lies at the interface of biology, physics, chemistry, and materials science. In addition, this research will be a close collaboration between a theoretical and experimental group from departments of chemistry and chemical engineering. These factors will combine to create a unique multidisciplinary research environment for participating students and research infrastructure. Considering the ethnic diversity at the University of Houston and in the greater Houston area, the research will enhance the educational opportunities in several underrepresented groups and promote their participation in advanced research. Existing collaborations with local writers and radio personalities will be utilized to publicize the societal benefits of the research. In addition to the fundamental and clinical significance of the research, its benefits include new potential routs for manufacturing novel materials and improving the nutritional value of crops. This project is jointly supported by Molecular Biophysics in the Division of Molecular and Cellular Biosciences and by the Physics of Living Systems program in the Physics Division.

为了发挥其功能，蛋白质必须在活细胞的拥挤环境中运作，因此需要防止蛋白质聚集的机制。当这些机制失败时，就会发生病理状况，如镰状细胞性贫血或斑块形成。另一方面，在某些情况下，特定类型的聚集实际上是期望的;实例包括胰岛素在胰腺中的储存和以晶体形式在谷物中的蛋白质。制造蛋白质晶体仍然是确定蛋白质结构的最重要工具，这对于理解蛋白质功能至关重要。令人惊讶的是，对于这些蛋白质聚集体的形成，折叠的蛋白质分子必须首先组织成长寿命的富含蛋白质的液体簇，其大小约为1微米：根据现有的相平衡范式，这种介观簇不应该存在，也没有在其他类似的系统中看到过，如胶体。该项目旨在阐明令人困惑的介观团簇形成的分子机制和热力学基础。为了实现这一目标，该项目将结合联合收割机的理论和实验的努力，卢布琴科和Vekilov实验室使用四种蛋白质作为模型系统：溶菌酶，血红蛋白，胰岛素和Lumazine合成酶。水结构在蛋白质-溶剂界面的作用和形成的短暂的蛋白质低聚物的稳定的蛋白质丰富的相将通过分子建模和测试的动态/静态光散射和热力学和流变学表征。丰富的动力学的形成/衰减的集群之间的相互作用蛋白质运输和低聚物的形成将制定出解决非线性动力学方案加上扩散/平流和测试对测量的寿命和集群的大小。 蛋白质浓溶液中介观聚集体的重要问题的解决是生物学、物理学、化学和材料科学的结合点。此外，这项研究将是来自化学和化学工程系的理论和实验小组之间的密切合作。这些因素将联合收割机，以创造一个独特的多学科的研究环境，参与学生和研究基础设施。考虑到休斯顿大学和大休斯顿地区的种族多样性，这项研究将增加几个代表性不足的群体的教育机会，并促进他们参与高级研究。将利用与当地作家和广播界人士的现有合作，宣传研究的社会效益。除了这项研究的基础和临床意义外，它的好处还包括制造新材料和提高作物营养价值的新的潜在途径。 该项目由分子和细胞生物科学部的分子生物物理学和物理学部的生命系统物理学项目共同支持。